Adjustment for inductances of variometers



' April 2, 1929. w. L. MacHUGH 1,707,950

' ADJUSTMENT FO R INDUCTANCES OF VARIOMETERS Filed July 28, 1924 3 Sheets-Sheet April 2, 1929. w. L. M HUGH ADJUSTMENT FOR INDUCTANCES OF VARIOMETERS 3 Sheets-Sheet 2 Filed July 28, 1924 April 2, 1929. w, MacHUGH 1,707,950

ADJUSTMENT FOR INDUCTANCEIS 0F VARIOMETERS Filed July 28, 1924 5 Sheets-Sheet 5 1 a); I: 7 man Patented Apr. 2, 1929.

UNITED rss WILLIAM L. macnuengor PHILADELPHIA, PENNSYLVANIA.

ADJUSTMENT FOR INTDIIFCTANGEE: 0F VABIOMETERS.

7 Application filed Ju1y-28,

My invention relates to variometers and. particularly to in'iprovement in wave length control; for different settings ot the var1ometer. l j The main purpose of my invention 1S to provide av novel" form of variom'eter well adapted to the needs oi service and easy and inexpensive to manufacture.

A further purpose is to balance the coils of the rotor quantitatively with respect to the coils of the stator, maintaining equal seltinductions in both whatever the adjustment with respect to the quantity of induction.

A further purpose is to have every coil ofthe rotor and'every coil of the stator balanced electrically with respect to every other coil of the variometer by dividingeach coil so as to always lie substantially symmetrically with respect tothe same point in the rotor axis, a point forming a common center of symmetryfor allwindings.

A furtherpurpose is to provide an interlinkage of switch members whereby the num-. beret coils in the rotor and stator. separate ly adjustable if desired, may be adjustable together in such manner as to maintain a predetermined relation between the numbers of coils simultaneously in circuit or the rotor and on the stator or in other words that the number of "urns in the rotor and the stator respectively may be increased or reduced together to maintain a conditionot numerical balance or numerical relation between them.

A further purpose is to make it possible to accommodate a variometer to lower ranges of wave length than previouslywithout losing its utility for higher wave lengths v A further purpose is to increase the delicacy of adjustment of the variometer.

My invention relates to the processes involved as well as to apparatus shown by which the processes may be carried out.

Further purposes will appear in the specification and in the claims.

Figure 1 is a front elevation of a desirable panel providing adjustment ofmy preferred construction.

Figure 2 is a section of Figure 1 upon line 22, the winding being omitted.

Figure 3 is'a section on line 33 of Figure 2. H I

, Figure 4 is a diagrammatic illustration of the preferred formof myinvention.

Figure 5. is a diagraimnatic illustration 1924. Serial No. 728,568.

showing the winding whereby my invention maybe carried out using any switch preterably the one shown in Figures 1 and l.

Figure 5? is a fragmentary view, a part of Figure 5 butcwith minor modification.

Figure 6 is a front elevation showing another torm 01" switch, providing if desired, an independent adjustment of the coils of the stator and of the rotor.

Figure 7 is a front elevation of a third form of switch, also providing an optional independent adjustment of the rotor and stator coils.

Figure 8 is a section of Figure 7 taken upon the line 88. I

Variometers for the purpose of adjusting inductances in radio circuits are of course well known. The rotor isordinarily given rotation adjustment throughout a range of a 180 between the positions for maximum and minimum inductanccs respectively. 1 In the position for maximum inductance the rotor coils are insnch position that the mutual inductance between the rotor and stator is most effective toward increasing the total inductance of the variometer, while at the other end of the range the mutual inductance is in position to be most effective to decrease total inductance.

In the prior art variometers have been set to different ranges of inductance tor variation by the position of the rotor by adjusting theturns of :one element to include a larger'or smaller number of turns within the active coil length, but so far as I am aware this adjustment in. the number of eltective turns has never been simultaneous to both stator and rotor.

My invention comprises provision for simultaneous adjustment of the effective turns on both statorv and rotor, with an adaption to alternative independent adjustment of the effective turns of each; provision for maintaining electrical balance between each coil unit of the variometer' with every other coil otthe variometer'; and provisionfor maintaining throughout the simultaneous adjustment equal inductions in the rotor and stator whereby the rotor and stator are adapted to most nearly neutralize each other when indirect opposition, thereby bringing the lower limits for the different settings most nearly to zero. Y

The alternative independent adjustments provide means for adjusting the relative dittlerence in the sell inductance of the active coils upon the rotor and stator while maintaining the same total number of effective coils and therefore substantially the same maximum inductance, obtaining inaxin'ium range with zero bias when there is the same number of effective coils on rotor and stator, and obtaining a series of progressively smaller ranges each having substantially the same maximum inductance by progressively increasing the relative dillerences between the sell inductances of rotor and stator.

In the upper parts of Figure 2, 1 have intended to show conventional views of rotor and stator omitting the windings. A minimum of distributive capacity is secured by placing the stator and rotor windings as close together as possible.

The variometer comprises, generally, standards 1t), 11 'toru'ling supports for a stator 12 initially split: in the plane oi the paper in Figure 2 so as to permit it to be assembled about the rotor 13. The rotor is rigid with a shaft 14-, supported in bearing 15 at one end and with a shaft 16 having a passage 16 through it for the withdrawal. of the connecting wires so that the coils in circuit may l e varied by connections outside of the rotor. The shaft 16 is supported lroi'n the frame in bearings 17.

The shaft 1 1 affords a mechanical connection be worn the rotor and an adjusting disc member 18 which is turned by a knurled liandie 19. For convenience in assemblage the shaft 1 1 made in two parts 20 and 21, united through threads 22 and a sleeve 28 which sleeve terms a conical fitting at 2 3: with, a corrcspoinling opening in the bearing member 25. As both of these parts, the sleeve and the bearing support are of metal, and as one is connected with one end ot the rotor coils as shown diagrammatically in Figure 41: at 26 and the hen ring member is connected with one end of the coils upon the stator as shown diagrammatically in Figure 1 at 27, the rotor and stator coils electrically connected by the engagement between any suitable member (such as the sleeve.) on the rotor and the surrounding bearing metal of the stator. For maintenance of this connection spring 29 is used.

The dial 18 indicates the degree o'li moven'icnt oi the rotor and may be limited to its usual range of movement 180 as by stops 31, 32.

In the formation of the rotor and stator, l have not intended to indicate the manner o't' winding whether plain winding or bank winding, for example, as the manner oi the winding as distinguished from the division of the windings into parts (preferably balanced as to turns of each coil on opposite sides of the casing) does not affect my invention.

In the. diagram in Figure 1 l have shown my prelt'crred form. The stator winding 33 is split up by taps into a munber oi turns, divided by tapping points into coil units 35, 3t), 37, 38, 39 and ll) with taps between the units leading out at 41, d2, d3, :ll, 4-5 and 4-6. These taps lead respectively to contacts L7, 48, 49, 50, 51 and 52.

The rotor winding]; coii'respondingly split up into coil units indicated at 53, 54, 55, 56. 57 and 58. Connections lead from the diilen ent lines between these coils at F9, (50, (31, (32. (i3 and (il. to contacts (35, (36, (37, ($8, (39 and 70.

Corresponding coils oi the rotor and stator preferably wound to have substantially equal iinluctances; -thus, the stator coils l5 i0 may or may not be equal to one another in inductance, but preferably are respectively equal to the corresponding coils of the rotor. When the variomctcr circuit includes coils 35--4t0 on the stator and coils oi? the rotor, the iinluetaimcs oi the rotor and stator are equal.

Qbviously one of the elements, preferably the stator, might be provided with additional coils having no counterpart on the other element, and adapted tor example to be bypassed or adjustably switched. into the first coil of the stator. When this is done a coin venicnt arrangen'ient is to have each oi the addit-ional coils wound for an inductance equal. to the sum of the imlurtances of coils ire -ll). Diagramnnitically this arrangement is indicated in Figure l: at C where switch C is adapted to throw any desired number oi the "oils C C C", G into the circuit oi coil assuming coils 35-40 of equal s ze and coils C"C" each equal to the sum oi coils filoit), it is evident that the settings of the sta or include the equivalents of any number ot' coils from 1 to 30 in number inclusive; further that between the limits of maximum variome'ter inductances corresponding to 12 coils and 31 coils respectively six ranges oi imlnctance variation is available to the rotor for each maximum number (as 12', 13, 14 29, P; of coils, according to the number oi the coils in the rotor circuit.

()bvionsly also the. number oi these additional coils may be varied to reach any range which may be desired, and by variation of the number ot these coils the total inductance represented by each and the number of subdivisions into which each one of the coils lit) llt)

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may besplit up by the taps provided in my invention, great delicacy, flexibility and varlety of ranges may be secured.

into two parts symn'ictrical with respect to the axis of rotation, which is much the preferred form and by which I secure electrlcal balance I of the active coils of the rotor with respect complete coil.

to each other and with respect to the active coils of the stator at all times.

axis and the other upon the other side of the axis; the two parts together making up the The several parts are shown by prime anu second markings, the coils 35, 36, etc., for example, being divided into two parts (turns or sets of turns) each indicated diagrainmatically in Figure at and 35 3(3' and 36 ,,ctc,throughout the stator coils. Likewise the coils 53, 54., etc., ofthe rotor being divided into two parts each (turns or sets of turns) 53 and 52 54 and 54 etc,

with theintent and result that the parts of I any coil always lie equally spaced on opposite sides o'fthe axis and are electrically balanced in their effectupon the correspondingly equally spaced stator coils which may be in actio at the time. a

I prefer during adjustments to automati-. (rally control the relation between the numbers of coils in active duty at any time upon the stator and upon the rotor respectively, and also to secure equality between these nunibers, giving at any time the'same selfinductance to thestator asto'the rotor.

This is normally advantageous for several reasons. Equality between the self induce tanccs of the stator and rotor is just the con (lit-ion .ElhWlTiClt there is nearest approach to neutralization of both inductanceswhen the stator and rotor are in position to directly. oppose one another, giving the nearest approach to Zero as the lower limit of each such range. "It also'secures several specially low ran having unusually'lowbut progressive ly higher maximums with extremely low (but progressively higher) minimums.

In the preferred form six coils are shown on the rotor and six on the stator with provision for coupling any number of coils from the one with the same number of coils of the other. v V

As best seen in Figure 5, I prefer to have the first coils nearest the center on both stator and rotor, working out from the center sequentially with the increase in number of coils.

I have shown in the drawings several advantageous forms of double switches to facilitate easy coupling of the coils in the manner indicated.

Each of the coils is therefore split.- up as seen into two parts, one of which l1es on. one side of the J i Describing first the simplest form, shown 1n Flgures l and 2 and diagrammatically in Figures 4 and 5, the contacts or terminals 4752 and 70 are grouped in arcs upon" opposite sides of the axis 71 within reach of contact fingers 72, 73 upon stripsl' l, 75. These strips, relatively electrically insulated, are carried by the disc 76 which is adapted to be turned to bring the fingers to engagement successively with thediiterent contacts. The opposite ends of these contact strips form contact fingers 77,178 engaging'with arcuate fixed contacts 79, 80 connected re spectively with terminals-81, 82' by which the variometer may be connected in the circuit.

When it is desired to have in the variometer circuit one coil of the stator and one coil of the rotor, the contact lingers 72 and 73 will respectively rest upon contact-"ten ininals 47 and 65, and to add successive coils the contact'fingers will pass in a clockwise direction to terminals 66, 48 and so on, and in every position equality is maintained between the numbers of coils'in stator and rotor respectively and therefore in the respec tive inductances of the rotor and stator.

Obviously the contact fingers may bridge the terminals. I

In the somewhatless compact form shown in Figure 6, the contact strips 74 and 75 are spaced axially and turn about spaced axes 71, 71 'to engage the contact terminals R-52 and 65--70. The strips are operatively linked or coupled by a bar 88 so as to traveltogether and to maintain the same number of coils in the rotor as in the stator. I By disconnecting the coupling bar 83 the switches are free for independent adjustinent, permitting a greater variety ofcoinbinations and securing some adjustments falling between those available when the strips arecoupled together and giving different ranges of inductances.

Each of the switch contacts may be aranged with coil-dead-end trail contacts 84 as seen in fragementary view B which' may,

be spaced inangular position to control one or more contacts in the rear of the switch. Asshown the trailing distances correspond with two contact positions In Figures 7 and 8 an alternative double switch is shown that is substantially the equivalent to the form'shown in Figure 6 but more compact. This form is one among many structures in which contact devices may be removably linked together to maintain during inductance adjustment an equality or predetermined ratio between the inductances of the rotor and stator with alternatively separate adjustment of these inductances.

In Figure 7 divided contacts 85 and 86 take the place of contact 74, of the other figures. a. stem 87 which affords a pivot for both con- These divided contacts i'initethrough tacts and which has two diameters S8 and S9. I he pivot passes through a preferably insulated sleeve 90 and is held in position by nut 91.

The double contact 92 corresponding to contact of the other form is movable about the pivot at the pointot larger diameter 88 and is insulated from it by Sleeve 93 and by disc 94.

The contact arms and 86 are both moved by handle 95 and the double .contact 92 is moved by a handle 96. So far as thus describedthese two contact arms, the double contact 85, 86 and the double contact 92 are wholly distinct and separate and may be moved separately to form any of the combinations of which the number of fixed cont-act plugs and joining coils for the stator and rotor is capable. In order to permit them to be coupled together for common movement I provide a screw pin 96 upon one of the arms which engages within an opening in an insulated lug 97 upon or in the other. ll'hen this screw and lug are engaged the contact arms operate in the same way as the contact arms of the term shown in the other figures.

It will be obvious that my invention is independent of the character oi the winding, whether bank or otherwise.

Its adaptation to maintain during inductance adjustment equal inductances in rotor and stator widens the ranges oi the rotor.

Its :ulaptation to independent adjustment ot the inductances of the rotor and stator permits close adjustn'lent to any desired maximum, and permits variation of the rotor ranges without any substantial variation in the total selt induclanccs ol the stator and rotor. i a,

And finally, the syn'nnetry of every coil with respect to the variomctcr axis and therefore with respect to every other coil, among other advantages provides electric balance "for all settin In view or? my invention and disclosure variations and modifications to meet individual whim or particular" need will doubtless become evident to others skilled in the art and I claim all such in so tar as they fall within the reasonable spirit and scope of my invention.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. In a variometer, a stator inductance and a rotor inductance and connected means for simultaneously :uijusting both induclances, the stator and rotor being relatively rotatable independently of the adjustment.

:3. In a variometer, substai'itially equal stator and rotor inductances and connected means for simultaneously adjusting both inductances with maintenance of substantial equality between the adj ustment-s.

3. In a varioineter, stator and rotor inductances, an adjustment for the stator inductance, a separate adjustment tor the rotor inductance, and means for coupling the adj ustments to operate together.

l. In a variometer, a rotor winding divided into sections, a stator winding divided into sections, contacts with which the divisions of the sect-ions are electrically connected and common means for connecting with the respective contacts to secure equality of winding in, the rotor and stator respectively independently oi rotation of the rotor and for a variety of di'lterent total windings.

In a variometcr, a rotor and stator in series with each other and each having its coil divided into sections, a series o'l. contacts connected with the rotor sections, a series of contacts connected with the stator sections, independently movable switch arms, one engaging each series of contacts to include more or tower coils in the circuit in each, and means for connecting the switch arms to move in unison.

(5. In a variometcr, a. rotor coil divided into sections, a plurality o't switch contacts to which the section terminals are connected, arranged to are shaped, a stator winding divided into sections, a plurality of switch contacts towhich the stator section terminals are connected, arranged about the same center as the are oi? the rotor contacts, switch lingers bearing upon the respective contacts and insulated from each other, common rotor means tor the switch tingers and contacts made by said switch lingers at the opposite ends thereof from the first contacts.

ILLIAM L. M AoI-IU GH.

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